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Mars Return Mission
Back to Mars Activities NASA, ESA, JAXA, Roscosmos and other space agencies are planning a manned mission to Mars, and Spaceflight Simulator offers us a way to test how such a mission would look. A Mars Return Mission is easier to do then a similar mission to Mercury or Venus. The Ship For a Mars return mission, we need a big ship with enough fuel. The biggest challenge is the fact that Mars has a rarefied atmosphere and the ship will require many parachutes and additional engine firing for landing. The game has no pre-built ships and any player is free to build its own spacecraft. The ship listed on top-right of this article is named Ana Express or simply AX (feel free to name it as you want in your game). It is a three-stage rocket with two double boosters on the third stage. It is ideal for return missions to Mercury, Mars and Venus. The first stage is made of seven big engines, with 140 t of fuel. The second stage has two big engines available for use with the first stage, together with 35 t of fuel. The other 5 engines, with their 100 t of fuel, are used only after the first stage is detached. The third stage has two detachable boosters, with a total of four small engines and 20 t of fuel. They also have two landing legs and two side parachutes. Because Mars has a rarefied atmosphere, it is better to replace the two side parachutes with some structural parts and attach more parachutes. For the best results, use 8 parachutes, four on each side. The central rocket of the second stage has a small engine, 10 t of fuel, a Capsule and a parachute. Liftoff The ship has enough fuel for the whole mission. If everything is done correctly, the central rocket of the third stage will return home with almost all its fuel unused, meaning there is room for errors. At launch, all seven engines of the first stage and the two separate engines of the second stage must be turned on, working at 100%. At 4000-5000 meters, where the atmosphere is denser, the ship must fly vertical to pass faster. After this, the ship must gradually turn aside. Above 10 km, Earth's atmosphere is rarefied and will not cause significant problems. The first stage needs to be separated when it runs out of fuel, then it will fall back to Earth. Earth Orbit The second stage will carry the used two engines and their fuel tanks. Because of the limited building space, there is no other way. While using the second stage, the ship has to change angle to gain Low Earth Orbit. In order to save as much fuel as possible, this must be done smoothly. The flight path must not get too far from the Karman Line. After gaining orbit, some correction maneuvers must be done to get an orbit as circular as possible. If everything is done perfectly, the second stage must still have a little fuel left. Cruise To Mars After gaining low Earth orbit, the player must then select Mars as a target, wait for a launch window and burn prograde. Accelerate the ship while it is close to Earth to take advantage of the Oberth effect. Set the ship to get very close to Mars, nearly touching the atmosphere. Important: Because of gravitational perturbations from the Moon, the flight path may fluctuate. If you want to be sure your ship will reach target, check the trajectory after leaving Earth sphere of influence. Fire the engine forward or backward if you want to adjust the trajectory. There are a few players who, to save some fuel, go for a Moon flyby first. This might not be needed. Mars has a rarefied atmosphere, which is ideal for aerobraking (see below). In order to do so, choose a flight path that will go slightly above half the Martian atmosphere. Mars Landing This is the most challenging part of the trip. There are 3 different approach techniques: #'From orbit'. For this, the ship must have a flight path above the atmosphere. Set your flight path as close to Mars as possible. Then, fire the engines retrograde when you are the closest to Mars to take advantage of the Oberth effect. Then, from orbit, fire the engines again to slow down the ship to an impact trajectory. #'Aerobrake'. Mars has a rarefied atmosphere, just enough for aerobraking. The ship should have a special trajectory. At closest approach, it should be at 3/5 height of the atmosphere. After the first pass, it will be slowed down just as needed to enter orbit, but with the perimars still set inside the atmosphere. If you set the path to cross the atmosphere at 1/2 of its height, you might not return to space and slowly fall towards Mars. If you set the path cross the atmosphere at 3/4 of its height, the ship might not be slowed enough and exit Mars sphere of influence. #'Direct impact trajectory'. If the path is set so that the ship will impact Mars directly, you need to fire the engines to slow down the ship. The atmosphere is not dense enough to slow the ship enough to land safely. No matter the technique used, the ship will descend to Mars. Once it is below 2500 m altitude, open the parachutes as fast as you can. If you want to use the AX ship or a similar variant, it is a good option to add many parachutes (eight should work good enough). To open them all fast enough, turn the ship on one side, open the four parachutes that are on the upper side, then the parachutes on the opposite side. Before touchdown, open the landing legs. If the ship still moves too fast, the landing legs might be damaged, but the engines might survive. Finally, two seconds before touchdown, fire the engines. To Mars Orbit This task is easy, because Mars has a rarefied atmosphere that does not present much resistance. Also, the gravity is far lower. If you are using the AX ship or a similar model, fire the four engines of the boosters, first on a vertical path, then turn the ship on one side. You might need to fire the engines from time to time to get into a low Mars orbit. If everything is done correctly, there should be enough fuel left in the boosters to leave Mars's sphere of influence. Phobos And Deimos It is good to explore Phobos first and Deimos later to save some fuel. If everything was done correctly, the ship should have enough fuel. The two small moons of Mars have low gravity, a fact that should allow us to explore them very easily. Both moons have very small spheres of influence. To get there, target one of them, find a good flight window and proceed. Carefully adjust trajectory. When entering the sphere of influence of a moon, fire the engines retrograde to slow down and enter orbit. Then, continue to slow down to get a free-fall trajectory. From time to time, fire the engines very slowly to slow down the ship to land. To escape the gravity of a moon, it is enough to fire the engines for a few seconds. If you want to get into orbit, a few engine burns should be just enough. To fly from Phobos to Deimos or back, you first have to escape from the moon's sphere of influence and orbit Mars. Then, you will see the flight window. Proceed carefully to get close enough to the targeted moon. Cruise Back If you are still orbiting Phobos or Deimos, escape their sphere of influence and start orbiting Mars. The flight window towards Earth is not visible from the orbit of a moon. If everything was done correctly, the ship should have enough fuel. Now, depending on how much fuel is left, a ship can gain Earth orbit or directly plunge into Earth's atmosphere. Earth has an atmosphere dense enough to slow down a ship that is not coming on a direct trajectory towards Earth's surface. If the chosen trajectory is closer to the atmosphere, the ship will be slowed down just enough to open the parachute and land safely. Alternative Version The Spaceflight Simulator Model Ship is suitable to send a ship on a one-way mission to Mars. With little improvement, this ship is incapable of returning from the surface of Mars. In order to do so, the ship will need: * Two extra boosters * Side parachutes for Mars landing. See Also *Mars *Mars Activities *What To Do In Spaceflight Simulator Category:Tutorial